1a: Yes. the second we have parity, we'll start turning it on by default for private rooms. We'll probably start with DMs, and we'll probably do a fairly soft roll-out to sneak in some final testing. Current status is that we have E2E Search working (github.com/matrix-org/seshat); we have E2E cross-signing almost done (https://dashboard.lant.uk/#/plan?epic=vector-im/user-stories... we have eyes on the remaining causes of undecryptable messages and are working through them. We're aiming for Jan.

3: Interesting. It could be a very temporary CPU saturation on the Matrix.org CPU master. We're working on sharding the master per-room to mitigate this, but it's going to be a few months to land.

4: Looks like there is a bug for this already - please upvote https://github.com/vector-im/riot-web/issues/10649.

Testing & reporting bugs is absolutely invaluable - thank you.